This project is a study of innovative change in the delivery of ambulatory care at a large university medical center. The Northwestern Universiy Medical School Clinics are being reorganized from traditional ambulatory clinics into a modern group practice serving both lower income and affluent patients. Its aim is to serve as a model of excellence, demonstrating the modern practice of medicine while serving as a resource for medical education and medical research. The long-run objectives of this research are to investigate how a change in the organization of medical care delivery affects: (1) the patient population in terms of socioeconomic and demographic characteristics, utilization patterns, and health status; (2) the attitudes of patients, attending physicians, residents and medical students on key aspects of care (e.g. accessibility, continuity, quality, and overall satisfaction); (3) the opinions of physicians, residents and medical students on the balance among teaching, research and service.